HRL Laboratories Creates World’s First X-Band N-Polar GaN MMIC

The New Monolithic Microwave Integrated Circuit Promises Disruptive Improvements in Radar, Communications, and Electronic Warfare

MALIBU, Calif. November 16, 2022— Researchers at HRL Laboratories, LLC, have fabricated and tested the world’s first X-band nitrogen-polar (N-polar) gallium nitride (GaN) monolithic microwave integrated circuit (MMIC), proving a concept that will enable disruptive improvements in defense electronic applications such as radar, communications, and electronic warfare. Completed entirely in-house at HRL’s Southern California facilities, the circuit demonstrated a gain of 14 dB at 6 GHz operating frequency.

Wafer of HRL Laboratories’ world-first N-Polar GaN devices. Copyright 2022 HRL Laboratories

“HRL innovates technologies like an academic institution, and delivers like a merchant supplier,” said HRL’s N-polar GaN task manager Dr. Erdem Arkun. “Although this is a first demonstration, it is by no means just a hero result. N-polar GaN is designed to be largely compatible with standard GaN MMIC fabrication processes used in HRL’s commercially available GaN multi-project wafer offering. We anticipate rapid maturation of the N-polar technology for limited initial release in the near future.”

N-polar GaN offers impressive efficiency, which is especially suited for power-limited airborne applications where it offers system-level benefits.

“Because of its high efficiency, N-Polar GaN is also low noise,” Arkun said. “As an example, this feature enables radar operation with less drain on aircraft power systems and more capability for target detection scenarios with less radiated power.”

N-polar GaN breaks the scaling versus sheet resistance trade-off in highly scaled GaN devices, which is a fundamental limit on how much the technology can be scaled. This accounts for the circuit’s greater efficiency compared to the Ga-polar versions. N-Polar GaN fabrication requires slightly different chemistry than typical semiconductors, a capability that not every facility has. HRL’s Microfabrication Technology Lab is well equipped to accomplish end-to-end creation of the N-polar GaN MMIC.

“HRL is pleased to demonstrate the world’s first N-polar MMIC. This is a significant milestone for N-polar GaN technology,” said HRL’s program manager Dr. Dan Denninghoff. “This achievement was possible because of the excellent HRL team and the support of our sponsor, Dr. Paul Maki from the Office of Naval Research, who has been at the forefront of GaN technology in the United States for more than 17 years.”

The HRL team plans to further improve the designs and fabrication flows and push the boundaries of N-polar technology to address W-band applications requiring higher efficiency and higher output power MMICs. Future applications also could benefit commercial technologies such as cellular 6G.

HRL Laboratories, LLC, Malibu, California (hrl.com) is a corporate research-and-development laboratory owned by The Boeing Company and General Motors specializing in research into sensors and materials, information and systems sciences, applied electromagnetics, and microelectronics. HRL provides custom research and development and performs additional R&D contract services for its LLC member companies, the U.S. government, and other commercial companies.

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